/*
 * @Descripttion: 
 * @version: 
 * @Author: wtzhang
 * @Date: 2021-07-02 09:27:06
 * @LastEditors: wtzhang
 * @LastEditTime: 2021-07-02 16:31:59
 */
//  let dom = document.getElementById(elementId: "box")
let sum1: (a: number, b: number) => number;
sum1= function (a, b) {
  return a + b
}
console.log(sum1(3, 2));